ORCHIS FAMILY. 323 



117. ORCHIDACE^, ORCHIS FAMILY. 



Herbs, with flowers of peculiar structure, the perianth adherent 

 to the one-celled ovary (which has numberless minute ovules on 

 3 parietal placentse), its chiefly corolla-like 6 parts irregular, 3 in 

 an outer set answering to sepals, 3 within and alternate with these 

 answering to petals, one of these, generally larger and always differ- 

 ent from the others, called the labellum or lip : the stamens are 

 gynandrous, being borne on or connected with the style or stigma, 

 and are only one or two; the pollen is mostly coherent in masses of 

 peculiar appearance. All perennials, and all depend upon insects 

 for fertilization. Beginners will not very easily comprehend the 

 remarkable structure of most Orchideous flowers. But our more 

 conspicuous common species may be readily identified as to genera 

 and species. 



§ 1. Epiphyte or Air-Plant Orchids. Of these a great variety are cultivated 

 in the choicest conservatories. We have one in the most Southern States. 



1. EPIDENDUM. The 3 sepals and 2 petals nearly alike and widely spreading: 



the odd petal or lip larger and 3-lobed, its base united with the style, which 

 bears a lid-like anther, containing 4-stalked pollen-masses, over the glutinous 

 stigma. 



§ 2. Terrestrial Orchids, gromng in the soil, in woods or low grounds. 

 * Anther only one, hut of 2 cells, which when separated (as in Orchis) must not he 

 mistaken for tivo anthers : pollen collected into one or vwre masses in each 

 cell : stigma a glutinous surface. 



•*- Lip or odd petal produced underneath into a free honey-bearing horn or spur: 

 pollen of each cell all connected hy elastic threads with a central axis or stalk, 

 the lower end of which is a sticky gland or disk, by adhesion to which the ivhole 

 mass of pollen is dragged from the opening anther and carried offhy insects. 



2. ORCHIS. The 3 sepals and 2 petals are conniving and arched on the upper 



side of the tiower; the lip turned downwards (i. e. as the flower stands on its 

 twisted ovary). Anther erect, its two cells parallel and contiguous ; the 2 

 glands side by side just over the concave stigma, and enclosed in a sort of 

 pouch or pocket opening at the top. 



3. HABENARIA. Flower generally as in Orchis, but the lateral sepals com- 



monly spreading; the glands attached to the pollen-masses naked and ex- 

 posed. 



4- -t- No spur to the lip ; anther borne on the back of the style below its tip, erect or 

 inclined: the ovate stigma on the front. Flowers in a'spike, small, white. 



4. SPIRANTHES. Flowers oblique on the ovary, all the parts of the perianth 



erect or conniving, the lower part of the lip involute around the style and 

 with a callosity on each side of the base, its narrower tip somewhat recurved 

 and crisped. Pollen-masses 2 (one to each cell), each 2-parted into a thin 

 plate (composed of grains lightly united by delicate threads), their summits 

 united to the back of a narrow boat-shaped sticky gland set in the beaked tip 

 over the stigma. Leaves not variegated. 

 6. GOODYERA. Flowers like Spiranthes; but the lip more sac-shaped, closely 

 sessile, and destitute of the callous protuberances at base. Leaves variegated 

 with white veining. 



••-•»-■•- No spur to the lip, or one adherent to the ovary: anther inverted on the apex 

 of the style, commonly attached hy a sort of hinge : pollen 2 or 4 separate soft 

 masses, not attached to a stalk or gland. 



++ Floioers rather large : pollen-masses soft, of lightly-connected pmodery grains. 



6. ARETHUSA. Flower only one, on a naked scape; the 3 sepals and 2 petals 

 lanceolate and nearly alike, all united at the base, ascending and arching 

 over the top of the long and somewhat wing-margined style, on the ppt-:i!-like 

 top of which rests the helmet-shaped hinged anther, over a little shelf, the 



